Effect of lethality on the extinction and on the error threshold of quasispecies

In this paper the effect of lethality on error threshold and extinction has been Studied in a population of error-prone self-replicating molecules. Forgiven lethality and a simple fitness landscape, three dynamic regimes can be obtained: quasispecies, error catastrophe, and extinction. Using a simple model in which molecules are classified as master, lethal and non-lethal Mutants, it is possible to obtain the mutation rates of the transitions between the three regimes analytically. The numerical resolution of the extended model, in which molecules are classified depending on their Hamming distance to the master sequence, confirms the results obtained in the simple model and shows how an error catastrophe regime changes when lethality is taken in account. (C) 2009 Elsevier Ltd. All rights reserved.